1. Field
The present disclosure generally relates to multi-chip modules (MCMs) for semiconductor chips. More specifically, the present disclosure relates to an MCM that includes assembly features with different reflow characteristics that are reflowed during assembly of the MCM.
2. Related Art
As integrated-circuit (IC) technology continues to scale to smaller critical dimensions, it is increasingly difficult for existing interconnects to provide suitable communication characteristics, such as: high bandwidth, low power, reliability and low cost. Engineers and researchers are investigating chip stacking in multi-chip modules (MCMs) to address these problems, and to enable future high-density, high-performance systems.
However, it is difficult to bond chips to each other and to carriers (such as printed circuit boards) in chip stacks using existing assembly techniques because of stringent requirements for alignment accuracy and manufacturing throughput. For example, if chips are bonded to each other using a silicone-based adhesive, a pick-and-place tool and non-standard fixturing may be needed to obtain the desired alignment.
Alternatively or additionally, an MCM may be assembled using balls and pits, in which adjacent chips in the MCM are aligned by placing the balls into collocated pits on surfaces of the chips. While this existing assembly technique can provide high alignment accuracy among the chips in the MCM, it typically involves multiple assembly operations, which makes assembly of the MCM complicated, time-consuming and expensive.
Hence, what is needed is a technique for assembling an MCM without the above-described problems.